Zubay G, Cheong L, Gefter M
Proc Natl Acad Sci U S A. 1971 Sep;68(9):2195-7. doi: 10.1073/pnas.68.9.2195.
Biologically active su(+) (III) tyrosyl-tRNA has been synthesized in a DNA-directed cell-free system from Escerichia coli. Such a system should be most useful for studying the mechanism of tRNA synthesis. This tRNA is capable of suppressing amber mutations in the gene coding for beta-galactosidase (EC 3.2.1.23) and, therefore, must be capable of being charged and transferring amino acids. A 4-fold stimulation in the activity of the tRNA formed de novo is obtained with isopentenyl pyrophosphate, a compound involved in the post-transcriptional acylation of an adenine base adjacent to the anticodon. It has been suggested elsewhere that formation of RNA subject to stringent control may be inhibited by guanosine tetraphosphate (ppGpp). However, guanosine tetraphosphate did not affect the synthesis of su(+)III tyrosyl-tRNA, even though the synthesis of this tRNA is subject to stringent control.
具有生物活性的琥珀抑制型（Ⅲ）酪氨酰 - tRNA已在大肠杆菌的无细胞DNA指导系统中合成。这样的系统对于研究tRNA合成机制应该是非常有用的。这种tRNA能够抑制编码β - 半乳糖苷酶（EC 3.2.1.23）的基因中的琥珀突变，因此，它必须能够被氨酰化并转运氨基酸。用异戊烯基焦磷酸可使从头合成的tRNA活性提高4倍，异戊烯基焦磷酸是一种参与反密码子相邻腺嘌呤碱基转录后酰化的化合物。其他地方曾提出，受严格控制的RNA的形成可能会被四磷酸鸟苷（ppGpp）抑制。然而，四磷酸鸟苷并不影响琥珀抑制型（Ⅲ）酪氨酰 - tRNA的合成，尽管这种tRNA的合成受到严格控制。
